Revolver type semiautomatic firearm



1969' v. N. VIRTANEN REVOLVER TYPE SBHIAUTQIATIC FIREARM 2 Sheets-Sheet1 Filed larch 28. 1968 INVENT OR ATTORNEY- Oct. 7, 1969 v, vm'r3,470,788

REVOLVER TYPE SEMIAUTOIATIC FIREARM Filed larch 28. 1958 2 Sheets-Sheet2 2" 'IIIIIIIIIIIIIIIII I FIG.7

INVENTQR N-Vil'tflflen ATTORN EYS United States Patent 3,470,788REVOLVER TYPE SEMIAUTOMATIC FIREARM Viljo Niilo Virtanen, Sornaistenrantatie 3 A 24, Helsinki 53, Finland Filed Mar. 28, 1968, Ser. No.716,931 Int. Cl. F41c 1/02 US. Cl. 89-155 7 Claims ABSTRACT OF THEDISCLOSURE A semiautomatic revolver-type firearm having a barrel fixedto a frame and a cartridge cylinder rotatable on the frame adjacent thebreech end of the barrel. A hammer controlled by a trigger mechanism isautomatically recocked after each firing by a movable slide displacedrearwardly by the recoil of a cartridge fired in a cartridge chamber ofthe cylinder aligned with the barrel. The firearm is initially cocked bymanual retraction of the slide by a manual cocking lever. Interlockingmeans included in the trigger mechanism and coacting with the slideprecludes release of the hammer from its cocked position when the slideis retracted. Detent means on the frame coacts with a cylinder rotatingmechanism to assure rotation of the cylinder only in a normal directionand the slide functions upon moving rearwardly and then forwardly torotatably index the cartridge cylinder forwardly by means of thecylinder rotating mechanism. Releasable detent means on the frame coactswith the slide to controllably retain the latter in either of tworetracted positions, one of which permits free spinning of the cylinderin its normal direction of rotation and the other of which holds theslide releasably in a non-firing position for single shot usage of thefirearm.

This invention relates to a semiautomatic revolver-type firearm in whichthe rotation of the cartridge cylinder is effected by a spring actuatedslide, which in turn is moved by the recoil action.

Conventional semiautomatic revolvers have several defects. One of themost serious ones is that the cylinder rotates partly or completelywhilethe bullet still is inside the barrel. Since the rotating mechanismreceives its energy from the backward movement of the cartridge case theimpetus of the cylinder may cause such a sudden and heavy stress on thegun parts that they cannot resist it, or then the kinetic energyimparted by the recoil to certain gunparts will be insufficient to cockthe gun. It may even happen that the cylinder will prematurely rotateinto its new position before the bullet has even reached the barrel,which will cause an inside explosion within the gun. Anotherdisadvantage of said conventional constructions consists in thecompletely unsolved problem how one should ensure that the cartridgecase will remain undamaged when under pressure the same begins itsbackward movement simultaneously with the bullet moving forward. In somesemiautomatic guns having ammunition boxes the problem is solved byallowing the complete barrel-and-lock assembly to move togetherbackward, giving the bullet time to leave the cartridge case. Adisadvantage of such guns is, however, that the barrel movement willdisturb aiming accuracy, and also that the moving masses areunnecessarily heavy causing a disturbing movement when the gun is fired.A further disadvantage of some semiautomatic revolvers is that thehammer must generate the rotation movement of the cylinder besidesdischarging its primary function, and therefore it cannot move freely.

It is the object of this invention to eliminate these disadvantages, thenovel feature of the firearm being that the slide in moving backward isadapted to cock the hammer, and, additionally, to cock a springactivated cocking lever movably jointed to the slide and instrumental inperforming the initial cocking of the gun and in executing the returnmovement of the slide. By means of the trigger mechanism the hammer andthe cocking lever are jointed to each other in such a way that thehammer will remain cocked irrespective of the position of the trigger,while the slide, without causing the cylinder to rotate, will impart arotating movement to a cylinder-rotating mechanism placed inside thecylinder, and further the slide will, on returning to its initialposition turn the cylinder-rotating mechanism in the opposite direction,the said rotating mechanism having been coupled to the cylinder.

A semiautomatic revolver type gun built according to the teaching ofthis invention will be reliable in operation, since during the fast andsudden movement caused by the created pressure the slide only will movebackward, its movement being softened by the thereto attached spring ofthe cocking lever. The slide is connected to a gear bush of only lowinertia and the same moves along a slot in the latter, this slot firstlyrunning parallel to the longitudinal axis of the gear bush, then spiralsalong the cylindrical surface and ends in a straight line again. Thiscreates a small gear bush torque requiring only very little energy.Moved by energy of the spring mechanism of the cocking lever the slidereturns to its initial position while turning the cylinder, by means ofthe gear bush mechanism, simultaneously to a new position. The hammerhas no other function but to ignite the charge.

Another advantage of the gun is it will not go off e.g., it dropped tothe ground, because the gun has a built-in hammer protected from shocks.Also, when the gun is cocked, the cylinder is always locked and cannotbe rotated forward. When the slide is pulled back to safety position thecylinder is free to rotate in its normal direction, thereby rendering itpossible to load and to empty the cylinder in this position. The safetyposition can readily be observed because the slide is disconnected fromthe cylinder and invisible within the frame. The breech distance equalszero because a spring will .at all times urge the slide against thebottom of the cartridge case therefore, on firing the case cannot hitthe slide with force. Further, the cylinder need not always be a fullcylinderit can be used as partial cylinder, e.g., for receiving only twoor three cartridges as is the case in some semiautomatic shotguns forhunting.

In order to avoid gas losses and bursting of cartridge case, in biggercalibred guns the slide may, when in closed position, be arranged topress against a removable cartridge chamber, provided with a packingbushing and with springs, inserted into the bore of the cylinder. Inthis case, when the charge is ignited the pressure will cause thechamber and the case to move backward together, the case thus remainingmotionless in relation to the chamber wall for the time needed by thebullet to detach itself from the case, the friction created preventingcase from tearing, and the packing bushing preventing gas losses thatwould reduce muzzle velocity of the bullet, while, pushing the breechdevice (the slide) backwards until the chamber stops, the casecontinuing its movement until stopped by the case block and the slidestill continuing its movement until finally, induced by the springmechanism of the cocking lever, said slide returns to its initialposition. While performing this return movement, the slide with the helpof the gear bush mechanism rotates the cylinder into a new position.

The accompanying drawing shows an embodiment of the invention, where:

FIG. 1 is a side elevational view of the firearm;

FIG. 2 is a vertical sectional view of the cartridge cylinder showingthe rotating mechanism located in its center;

FIG. 3 is a vertical rear end view of the cylinder showing the cartridgechamber bores, the central bore and the guiding bars of the slide withtheir locking slots.

FIG. 4 is a vertical side view showing, partially in section, the slidemechanism, the hammer, the cocking lever with spring mechanism andtrigger mechanism;

FIG. is a horizontal top view and a vertical front end view of the slidesafety gear and the case block;

FIG. 6 is a vertical, partly sectional side view of the detachablecartridge chamber fitted into a sectional view of the cylinder. Part ofthe barrel and of the frame are visible, partly in sections.

FIG. 7 shows the bipartite slide, the moving end thereof, partly insection.

In FIG. 1 detail 1 is the frame of the gun on which barrel Is ismounted. Into aperture 1a is mounted cartridge cylinder 2 supported byand rotating on spindle 6. Behind aperture 1a and centering to barrelaxis is another aperture 1b for case block 12. Behind the latter is athird opening for safety catch 13. Above the safety catch and movable inlongitudinal frame opening is cocking lever 17 of the gun. Hammer 38which is located completely inside the frame, is shown in FIG. 4. Belowthe frame and inside the trigger guard 1 are trigger 27 and countertrigger 34 attached to the frame. The counter trigger 34 increasessensitiveness of first trigger 27. Adjusting screw 45 in a threaded borein front part of trigger guard is used for adjusting of counter trigger34. In front of the cylinder is shown cylinder safety catch 8, the lowerpart of which is fixed to the frame while hooklike upper part of thesame reaches to the gearing 4a of gear bush 4 (FIG. 2) which rotatescylinder. In front of the safety catch peg 5b is fixed transversely tothe frame, said peg locking the cylinder spindle to its place.

As shown in FIG. 2 the rotating mechanism of the cylinder is mounted onspindle 6 which attaches cylinder to the frame. The cylinder is rotatedby gear bushings 3 and 4 mounted on said spindle. Of these, bushing 4 isfixed to the cylinder by means of groove 4b in the cylinder and acorresponding ridge on the bushing. Contrarily, bushing 3 is freelymovable in center bore of the cylinder. Additionally, both bushings aretorsionally turnable on spindle 6, bushing 3 moreover movable lengthwiseon said spindle. For torsional movement bushing 3 is provided with slot3a near its rear end, cam 11 on underside of slide 9 fitting into saidslot 3a (FIG. 4). Said slot 3a in surface of bushing consists of twostraight lengths with connecting spiral line part in middle. The spacingbetween both ends of said slot is same as spacing of cartridge bores ofcylinder. Slide cams movement from end to end of slot then causestorsional turning of bushing, turned angle corresponding to slotsspacing. End of bushing 3 opposite bushing 4 is formed to one sideoblique gearing into which will fit corresponding gearing of bushing 4.In order to ensure turning in one direction only of bushing 4 and ofcylinder attached thereto, gearing 4a of bushing 4 is of a type whichhook 8 in frame (FIG. 1) will allow to turn in one direction only. Tosupport described bushing construction, front end of spindle 6 carries athird bushing 5 with bore 5a, spindle 6 being provided with a cut (notshown) located correspondingly. By means of trunnion 5b (FIG. I)inserted in a bore in gun frame, the cylinder with its spindle are fixedto gun and the bushing arrangement is supported on spindle. In bushingend spindle 6 additionally carries spring 7 leaning against shoulder onspindle, said spring at all times urging bushing 3 against middlebushing 4 in such a way that when oblique gearing slips over it, saidbushing yields elastically, but turning in opposite direction makesoblique gearing rigidly enough couple bushings together.

In accordance with FIGS. 2-3 the cylinders rear side is provided withstop ridges 2a located in pairs on each side of cartridge chambers.Thus, slide occupying forward position cam 11 on same is braced againstthe sides of corresponding groove, keeping the cylinder immovable when ashot is fired.

FIG. 4 is a side view showing, partly in section, the slide, trigger andsear mechanism, in aperture 1a belonging cylinder omitted. Slide 9 isfitted to move behind cylinder in slot made in barrel extension. Frontpart of slide holds a conventional nest 10 for hammer, cam 11 beinglocated to begin from hammers front end. The purpose of cam 11 has beenexplained above. In rear end of slide, behind hammer, out 9b providesspace for the movement of hammer 38 which is jointed to the frame by pin39. In the vicinity of the rear end, at a right angle to the cut isshown another cut 9a into which is fitted an up and down movable guidingpart (not shown), whereto cocking lever 17 is jointed by means of pivotpin 18. Said cocking lever 17 is jointed to the frame by means of pivotpin 19. By pins 20a and 20b linking part 20 connects cocking lever withspring adjuster 21, which in turn is fixed to frame by pin 22.Compressing spring 24 exerts pressure via spring rod 23 on springadjuster and thereby on cocking lever and slide. When centers of pins20a, 20b and 22 form a straight line, spring pressure reaches itsmaximum (cocking lever is motionless), but pressure ceasesproportionally as pin 20b is moved in direction from left to right inFIG. 4. By pivot pin 26 to frame fixed releasing lever 25 makes possiblethe functioning of the trigger and cooking mechanisms proper.Transversely in both ends of releasing lever 25 are pegs of which oneengages not-ch in bottom end of cocking lever and the other one inmoving up and down imparts movement to sear releaser 30. Pushed byspring 28 releaser hook 30a catches trigger 27 which is fixed to theframe by pivot 31. Sear releaser 30 is jointed to one end of sear 32 bypin 31 and will move the distance necessary Within a slot made intrigger. Pushed by spring 36 upper end of sear 32 engages sear shoulder38a of hammer 38, while the other end of said spring presses againstsensitizing counter trigger 34 which pivots on its to the frame fixedpivot pin 35. Sear 32 is jointed to the frame by pin 33. Upper end ofhammer spring 40 is braced against peg 3812, the necessary cut for thespring having been made in hammer.

FIG. 5 shows slide with gearing grooves 9c and 9d which arrest hook inend of safety catch 13. Frame cut 10 for safety gear is formed to risein forward direction in such a way that when lever 14 is pushed to frontend of safety catch, hook will not contact slide 9. The safety gear isfixed to the frame by pin 15. Bore in the opposite end of safety gearholds compression spring 16 which leans against frame and urges safetygear into safety position. Cut 1b in frame (FIG. 1) holds case block 12which runs partly also in groove in slide side surface.

FIG. 6 shows (partly in section) removable cartridge chambers 41, 42, 43especially intended for bigger calibre guns. The chamber formed by an incylinder bore removably inserted socket-like part of a sizecorresponding to calibre of gun, thinned in rear end to protrudeslightly from cylinder plane, is leaning against shoulder in cylinderbore. Compression spring 42 and packing bushing 43 are inserted inthinned front end of said part. Compression spring pushes packingbushing against barrel and the chamber against said shoulder in cylinderbore-the chamber being dimensioned to leave a narrow slit betweenchamber and barrel to enable cylinder to rotate. FIG. 6 shows partly insection expansion in rear end of barrel into which fits front end ofchamber. Pushed by slide, front end of chamber either moves into saidbarrel expansion or will press tightly against rear end of barrel whenshot is fired. Chamber recoil caused movement backward lasts a momentonly, yet long enough for bullet to leave case without damaging itforthe time of this movement case remains in contact with chamber walls.When bullet has left, pressure ceases and chamber movement stops butcase movement continues as well as slide mechanism movement causedthereby.

Bipartite slide used in bigger calibre guns as well as its movable end 9is shown in FIG. 7, partly in section, the slide mounted on end thinnedfor that purpose. This movable end is able to perform a to-and-fromovement of a fixed length within a part 1d of slide bore widened forthat purpose, this robust end also functioning as case block morereliably than the case blocks used in smaller calibre guns; where caseblock 12 is satisfactorily reliable and does not require change in formof case and its bottom. Necessary friction is provided by two springs(not shown) which make end 9 function without disturbances.

The gun works as follows: when cocking lever 17 is pulled backward byits spur, slide 9 moves backward simultaneously moving hammer 38 intococked position. The movement of cocking lever 17 sets spring 24, thetension of which can be kept almost constant, and even corresponding toinitial tension, in various positions of the spring, by the use ofadjusting lever 21. End of releasing lever 25 in notch of bottom part ofcocking lever 17 now moves upward causing its other end to push searrelease 30 free from contact with trigger 27. Spring 36 now moves upperend of sear 32 against cocking shoulder 38a thereby cocking hammer 38.While slide 9 moves backward its cam 11 moves in slot 3a in surface ofbushing 3, firstly parallel to spindle so long a distance that the endof slide 9 is released from locking bars 2a, then proceedin spiralformed part of slot in bushing simultaneously turning bushing the angleof one spacing step. Owing to the resistance of gearbush hook 8 andgearing 4a of counterbushing 4 cylinder 2 has not moved from itsposition. By means of ridge 4b of the cylinder the counterbushing 4 andthe cylinder are immovably anchored to each other.

During return movement of cocking lever 17 cam 11, moving in slot 3a,turns bushing 3 the angle corresponding to the spacing of slot 3a,simultaneously and coupled by the gearing of the gear bushings, cam 11turning cylinder as well to a new position. Now the gun is cocked forfiring-finger possibly on trigger should be moved forward to let spring28 actuate trigger 27 forward and hook 30a of sear release 30 to engagetrigger. Counter trigger 34 being pushed forward, cocking shoulders ofsear 32 and hammer 38 move as near shot release point as possible,shortening firing movement of trigger 27. Adjustable by means of screw45, the functioning of the countertrigger brings the advantage thatupper end of sear 32, ie the cocking hook, when engaging hammers cockingshoulder 38a, can penetrate to the bottom, making the gun remain cockedin spite of the jolt caused by shot fired, yet easy to fire thanks tocounter trigger. When charge is ignited by blow of hammer 38 on strikerthe case tends to move backward, causing same sequence of movements asabove, starting from pulling the spur of cocking lever 17, the casehowever stopping at case block 12. If the case block is so far back thatthe case completely leaves the cylinder the case will fly off from gun,whereas, if the case block is so placed that a part of the case remainsin cartridge'chamber, the case Will remain so, but it is easilydetachable by hand. This brings the advantage that the cases will notfly about or inconvenience the man next to the marksman. The ceases alsoremain faultless for reloading.

When the charge is ignited a strong pressure will hit the wall of thecase itself, and also cause strong friction in the case wall. The casemay even burst or break. But if the cartridge chamber 41 is movablelongitudinally it is possible to prevent case bursting, since for amoment the case moves backward together with the cartridge chamber,giving the bullet time to leave the case.

The guns way of functioning is regulated from the safety gear. Thesafety gear lever 14 is moved right to pin 15 which allows spring 16 tourge hook of safety catch 13 towards the slide. When slide 9 is movedbackward by spur of cocking lever 17, the hook of safety catch 13firstly takes hold in groove 90. This allows cylinder to rotate in itsnormal direction and the chambers may be loaded with cartridge.Thereafter the spur is pulled fur-- ther backward until the hook ofsafety catch 13 takes hold in groove 9d. The slide 9 is now in itsbackward position. Pushing the rear end of safety gear releases the hookand the slide can return to its initial position. All the movementsequences previously described have been carried out and the gun may befired. Thereafter the slide 9 automatically moves to its backwardposition. If you want the slide automatically and immediately to returnto its initial position, you have only to move lever 14 toward the hook.

The invention is claimed as follows.

1. A semiautomatic revolver-type firearm comprising in combination aframe, a barrel fixed on said frame, a cartridge cylinder defining anannular series of angularly spaced cartridge chambers rotatably mountedon said frame and disposed at the breech end of said barrel, a hammermovable between a cocked position and a firing position for firing acartridge in said cylinder, first spring means for urging said hammerfrom said cocked position to said firing position thereof, a triggermechanism coacting with said hammer to releasably retain the latter insaid cocked position thereof and including a trigger operable normallyto release said hammer for spring movement from said cocked position tosaid firing position, a slide movably mounted on said frame for movemen:between a normal forward position and a rearward retracted position,second spring means coacting with said slide to urge the latter to itsforward position, said slide coacting with said hammer to cock thelatter as an incident to retraction of the slide, a manual cocking levercoacting with said slide to effect manual retraction of the latter tocock the firearm whereupon the slide is returned to its normal forwardposition by said second spring means, said slide coacting with saidcartridge cylinder to be moved rearwardly to its retracted position bythe recoil of a cartridge fired in said cylinder thereby effectingcocking of said hammer, said trigger mechanism including linking meansinterconnected between said movable slide and said hammer to retain thecocked hammer in its cocked position independently of the position ofthe trigger while the slide is retracted from its normal forwardposition, a cylinder rotating mechanism disposed within said cylinder,said cylinder rotating mechanism including cylinder rotating meanscoacting with said slide to be rotated by the latter as an incident torearward movement of the slide without rotating the cylinder, and saidcylinder rotating means coacting with said slide and said cylinder torotatably index the latter as an incident to forward movement of theslide to its forward position.

2. A firearm according to claim 1 in which said cartridge cylinderdefines a central bore generally coaxial therewith, said rotatingmechanism is disposed in said central bore of said cylinder, a spindleis supported on said frame and said rotating mechanism is mounted on thespindle, said rotating mechasism including an axially movable gearbushing defining thereon a cylindrical surface and defining therein acam slot having a portion thereof extending axially with respect to thegear bushing and having another portion of generally helical shapeextending along the gear bushing, a cam on said slide movably engagingsaid cam slot for imparting to said bushing a rotary movementcorresponding to the angular extent of said cam slot about the axis ofsaid gear bushing, said rotating mechanism including a counter gearbushing disposed in coaxial alignment with said gear bushing, said gearbushing and said counter gear bushing having adjacent ends definingcoacting gears shaped to transmit rotary motion of said gear bushing tosaid counter gear bushing in one direction while allowing free rotationof said gear bushing relative to said counter gear bushing in theopposite direction, said coacting gears having a plurality of angularspacings respectively equal to the angular spacings of said cartridgechambers in said cylinder, a compression spring mounted on said spindleand coacting with said gear bushing and said counter gear bushing tourge said bushings into yieldable engagement with each other, saidgearing on said gear bushing and gearing on said counter gear bushingthereby continuously conditioning said gear bushing to turn said countergear bushing in said one direction while allowing said gear bushing torotate in said opposite direction relative to said counter gear bushing,said counter gear bushing defining thereon a protuberance, saidcartridge cylinder defining a slot receiving said protuberance on saidcounter gear bushing to preclude relative rotation of said cylinder andsaid counter gear bushing, a detent mounted on said frame, gearingrotatable with said counter gear bushing and coacting with said detentto preclude rotary indexing of said cylinder in said opposite directionand to allow rotary indexing of said cylinder in said one direction, ananchoring bushing disposed in said frame and receiving said spindle incontact with said counter gear bushing, said anchoring bushing defininga peg bore therein, said spindle defining a peg notch aligned with saidanchoring bushing bore, said frame defining a peg bore aligned with saidpeg bore in said anchoring bushing, a peg extending into said peg borein said frame, and said peg bore in said anchoring bushing and said pegnotch in said spindle to attach said rotating mechanism to said frameand prevent rotation of said spindle relative to the frame.

3. A firearm according to claim 1 in which said hammer is supported onsaid frame by a pivot pin and said slide defines a cut therein forreceiving the hammer, said hammer defines a sear shoulder thereon; saidtrigger mechanism including a sear, a pin pivotally supporting said searand a spring urging said sear into engagement with said sear shoulder onthe hammer to retain the hammer in cocked position; a pivot pinsupporting said trigger on said frame, said trigger mechanism includinga scar releaser pinned to said sear and having a hook cooperating withsaid trigger to effect in response to actuation of said trigger releaseof said hammer from said cocked position thereof for movement of saidhammer by said first spring means to said firing position, a firing pindisposed at the rear of said cylinder for engagement by said hammer tofire a cartridge in the cartridge chamber aligned with said barrel, saidcocking lever having a pin thereon coacting with a slot in said slide toeffect by means of said cocking lever manual retraction of said slide toinitially cock the firearm, said cocking lever being swingably supportedon said frame by a pivot pin, said linking means in said triggermechanism includes a releasing lever pivotally supported on said frameand coacting with said sear releaser, said releasing lever having a pinthereon coacting with a notch in said cocking lever to actuate saidreleasing lever when said slide is retracted from its forward positionto render said trigger inoperable to actuate said sear releaser torelease said hammer from its cocked position while said slide isretracted from its forward position.

4. A firearm according to claim 1 in which said cylinder defines in therear end thereof a plurality of guiding bars intervening between thesuccessive cartridge chambers and being separated successively bylocking recesses therebetween, said slide defines on the undersidethereof a cam positioned to fit into a locking recess in said cylinderaligned with said cam when said slide is in its forward position to fixsaid cylinder against rotation with the corresponding cartridge chamberaligned with said barrel.

5. A firearm according to claim 1 in which said slide comprises aforward first part adjacent the rear end of said cylinder and a secondpart extending rearwardly from said first part, said second slide parthaving a forward end thinned and engaging said first part in movablerelation thereto, said frame defining therein a bore receiving saidfirst slide part and being dimensioned to allow rearward movement ofsaid first slide from its forward position to an extent which is limitedto a range less than the range of rearward movement of the second slidepart.

6. A firearm according to claim 1 in which said slide defines in oneside thereof a longitudinal slot, said frame defines a frame slotaligned with said last mentioned slide slot, a case lock is fixed tosaid frame in said last mentioned frame slot and extends into said lastmentioned slide slot to determine a rearmost cartridge position to whicha cartridge fired in said cylinder can recoil against said slide.

7. A firearm according to claim 1 in which said slide defines on theforward end thereof slide arrest grooves, a safety catch, a pinpivotally supporting said safety catch on said frame, said safety catchhaving on a forward end thereof an arrest hook aligned with said slidearrest grooves, a spring coacting with said safety catch to urge thelatter swingably in a direction to engage said arrest hook thereon witheither of said arrest grooves in said slide when the latter is in aretracted position thereof, limit stop means movably supported on saidsafety catch for adjustable displacement therealong, means on said framecoacting with said limit stop means when the latter is adjusted to aposition thereof near said arrest hook to hold said arrest hook in aninoperative position free of engagement with said arrest grooves so thatsaid slide can move in either direction free of restraint by said safetycatch, said limit stop means when adjusted to a position remote fromsaid arrest hook releasing said safety catch to engage said arrest hookselectively with one of said arrest grooves when said slide is in afirst slide position to allow said cartridge cylinder to rotate freelyin said one direction and to engage said arrest hook with the otherarrest groove when said slide is in a second retracted position to holdsaid slide against forward return movement for controlled subsequentrelease by said safety catch for single shot functioning of the firearm.

References Cited UNITED STATES PATENTS 726,109 4/1903 Stow 89-155 XBENJAMIN A. BORCHELT, Primary Examiner STEPHEN C. BENTLEY, AssistantExaminer US. Cl. X.R. 4265

